Technical Field
The present specification relates to a vehicle door frame structure.
Related Art
Patent Document 1 (Japanese Utility Model Application Laid-open (JP-U) No. 563-112132) discloses an automobile door sash structure in which a sash is configured by an outer sash and an inner sash. Furthermore, a latch reinforcement is integrally formed on the rear side lower end portion of the inner sash. For this reason, the number of parts of the inner sash can be reduced. Examples of other related documents include Japanese Patent Application Laid-open (JP-A) No. H03-010929 (patent document 2), JP-A No. 2001-080361 (patent document 3), and Japanese Patent No. 5,561,445 (patent document 4).
In this connection, in a frame member (frame reinforcement) such as an inner sash that configures a sash, in order to raise the strength of a reinforcement portion such as the latch reinforcement, there are cases where the plate thickness of the reinforcement portion is increased. In this case, when the plate thickness of the entire frame member (frame reinforcement) is increased to match the strength of the reinforcement portion, there is the problem that the weight of the entire frame member (frame reinforcement) becomes heavier and therefore the weight of the entire vehicle door becomes heavier.